Well-known examples of biopolymer analysis using DNA sequencing are taught, for example, in F. Sanger, et. al., DNA Sequencing with Chain Terminating Inhibitors, 74 Proc. Nat. Acad. Sci. USA 5463 (1977); Lloyd M. Smith, et. al., Fluorescence detection in automated DNA sequence analysis, 321 Nature 674 (1986); Lloyd M. Smith, The Future of DNA Sequencing, 262 Science 530 (1993). These and all other publications and patents cited herein are incorporated herein in their entireties by reference.
Known capillary electrophoresis systems and methods can require laser-induced fluorescence for exciting marker compounds or markers, such as dye molecules typically used to label analytes. Unfortunately, laser apparatuses are expensive to use, energy inefficient, consume large amounts of power, and are physically large, rendering electrophoretic systems incorporating lasers cumbersome to use.
The use of sources of irradiation other than lasers for the excitation of marker compounds provides many advantages. Although the use of light emitting diodes (LED's) for generating fluorescence in dye molecules is taught, for example, in U.S. Pat. Nos. 6,005,663 and 5,710,628, the contents of which are incorporated herein in their entireties by reference, the use of LED's in such electrophoretic methods typically results in low signal strengths and detection sensitivity that is only marginal. The low signal strength tends to impair adequate detection of marker compounds.
Electrophoresis arrangements that employ complex optics causing a reduction of the collecting efficiency of the detector also result in low sensitivity. The low sensitivity is aggravated through the use of LED's, which compromise sensitivity in the first instance. The problem of lowered sensitivity through LED use is further exacerbated when using multiple-channel-type electrophoretic devices, that is, electrophoretic devices using an etched plate with capillary-sized grooves, or using a plurality of capillary tubes, where either type of device has multiple-channels used to increase throughput.
An electrophoretic apparatus and method that include a cost-effective and convenient source of irradiation and that do not compromise sensitivity or resolution would be desirable, especially in multiple-channel electrophoretic systems used to increase throughput.